Apparatus having partially gold-plated surface

Abstract

A change in the surface properties of apparatus for pharmaceutical preparation results from steam sterilisation. This change may be avoided by the use of apparatus with more hydrophilic post-sterilisation surfaces, e.g. those of gold. Hence there is provided a process for the preparation of a mixture comprising a discontinuous phase in a continuous phase which comprises using a mixing apparatus having a non-porous mixing surface which is repellant to the discontinuous phase and/or attractive to the continuous phase when the continuous phase is liquid or which is attractive to the discontinuous phase when the continuous phase is gaseous, whereby to improve the efficacy of the preparation of said mixture and/or to reduce physical degradation of said mixing surface, said surface if hydrophilic being more hydrophilic after sterilisation than is stainless steel and if hydrophobic being more hydrophobic after sterilisation than is stainless steel.

What is claimed is:  
     
         1 . A process for the preparation of a mixture including a discontinuous phase in a continuous phase which comprises using a mixing apparatus having a non-porous mixing surface which is attractive to the continuous phase when the continuous phase is liquid or which is attractive to the discontinuous phase when the continuous phase is gaseous.  
     
     
         2 . The process of  claim 1  wherein said mixing surface is more hydrophilic after sterilisation than is stainless steel.  
     
     
         3 . The process of  claim 1  wherein said mixing surface is more hydrophobic after sterilisation than is stainless steel.  
     
     
         4 . The process of  claim 1  wherein the mixing surface is repellant to the discontinuous phase.  
     
     
         5 . The process of  claim 1  wherein said continuous phase is an aqueous liquid.  
     
     
         6 . The process of  claim 1  wherein said surface is made of or coated with gold or a ceramic material.  
     
     
         7 . The process of  claim 1  wherein said surface is plasma oven treated.  
     
     
         8 . The process of  claim 5  wherein water receding contact angle of said surface after steam sterilisation is less than 55E.  
     
     
         9 . The process of  claim 1  wherein said mixture is a pharmaceutical composition.  
     
     
         10 . The process of claims  1  wherein the continuous phase is an aqueous liquid and the discontinuous phase is at least partially gaseous.  
     
     
         11 . The process of  claim 1  wherein said mixing apparatus is selected from homogenizers, atomizers, sonicators, cap mixers, shakers, paddle mixers, blade mixers, static mixers, expansion nozzles, rotor stators, and extruders.  
     
     
         12 . The process of  claim 1  wherein said surface is steam sterilised before mixing.  
     
     
         13 . The process of  claim 1  for the preparation of a hydrophilic droplet-in-gas spray, wherein the mixing apparatus is a spray nozzle having a surface which is more hydrophilic than sterilized steel.  
     
     
         14 . The process of  claim 1  for the preparation of a hydrophobic droplet-in-gas spray, wherein the mixing apparatus is a spray nozzle having a surface which is more hydrophobic than sterilized steel.  
     
     
         15 . A gold plated rotor:stator assembly.  
     
     
         16 . An assembly comprising a sonicator horn or other actively vibrating surface placed in a sonicating chamber wherein at least part of the surfaces of said assembly are gold plated.  
     
     
         17 . An extruder having a filter chamber comprising a filter membrane disposed on a support, characterised in that at least part of the surfaces within said chamber are gold plated.